harfbuzz/src/hb-draw.hh

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/*
* Copyright © 2020 Ebrahim Byagowi
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#ifndef HB_DRAW_HH
#define HB_DRAW_HH
#include "hb.hh"
struct hb_draw_funcs_t
{
hb_object_header_t header;
hb_draw_move_to_func_t move_to;
hb_draw_line_to_func_t line_to;
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hb_draw_quadratic_to_func_t quadratic_to;
bool is_quadratic_to_set;
hb_draw_cubic_to_func_t cubic_to;
hb_draw_close_path_func_t close_path;
};
struct draw_helper_t
{
draw_helper_t (const hb_draw_funcs_t *funcs_, void *user_data_)
{
funcs = funcs_;
user_data = user_data_;
path_open = false;
path_start_x = current_x = path_start_y = current_y = 0;
}
~draw_helper_t () { end_path (); }
void move_to (hb_position_t x, hb_position_t y)
{
if (path_open) end_path ();
current_x = path_start_x = x;
current_y = path_start_y = y;
}
void line_to (hb_position_t x, hb_position_t y)
{
if (equal_to_current (x, y)) return;
if (!path_open) start_path ();
funcs->line_to (x, y, user_data);
current_x = x;
current_y = y;
}
void
quadratic_to (hb_position_t control_x, hb_position_t control_y,
hb_position_t to_x, hb_position_t to_y)
{
if (equal_to_current (control_x, control_y) && equal_to_current (to_x, to_y))
return;
if (!path_open) start_path ();
if (funcs->is_quadratic_to_set)
funcs->quadratic_to (control_x, control_y, to_x, to_y, user_data);
else
funcs->cubic_to (roundf ((current_x + 2.f * control_x) / 3.f),
roundf ((current_y + 2.f * control_y) / 3.f),
roundf ((to_x + 2.f * control_x) / 3.f),
roundf ((to_y + 2.f * control_y) / 3.f),
to_x, to_y, user_data);
current_x = to_x;
current_y = to_y;
}
void
cubic_to (hb_position_t control1_x, hb_position_t control1_y,
hb_position_t control2_x, hb_position_t control2_y,
hb_position_t to_x, hb_position_t to_y)
{
if (equal_to_current (control1_x, control1_y) &&
equal_to_current (control2_x, control2_y) &&
equal_to_current (to_x, to_y))
return;
if (!path_open) start_path ();
funcs->cubic_to (control1_x, control1_y, control2_x, control2_y, to_x, to_y, user_data);
current_x = to_x;
current_y = to_y;
}
void end_path ()
{
if (path_open)
{
if ((path_start_x != current_x) || (path_start_y != current_y))
funcs->line_to (path_start_x, path_start_y, user_data);
funcs->close_path (user_data);
}
path_open = false;
path_start_x = current_x = path_start_y = current_y = 0;
}
protected:
bool equal_to_current (hb_position_t x, hb_position_t y)
{ return current_x == x && current_y == y; }
void start_path ()
{
if (path_open) end_path ();
path_open = true;
funcs->move_to (path_start_x, path_start_y, user_data);
}
hb_position_t path_start_x;
hb_position_t path_start_y;
hb_position_t current_x;
hb_position_t current_y;
bool path_open;
const hb_draw_funcs_t *funcs;
void *user_data;
};
#endif /* HB_DRAW_HH */